As is well known in the gas turbine engine art, the durability of engine components is of paramount importance and, obviously the longer an engine component endures, the longer an engine can perform without the costly shutdown of the airplane necessitated by the repair or replacement of such components. It is therefore a constant concern to develop components that can withstand the hostile environment to which they are subjected. As to be expected, one area that has been particularly troublesome is in the combustor and particularly where the fuel nozzles interface with the combustor liner. The fuel nozzle guide that seals the fuel nozzle at the front end of the annular combustor has been subjected to extraordinary thermal stresses and has heretofore been a maintenance problem.
Heretofore, the heat shield was made integral with the liner wall. The heat shield not only served to protect the nozzle structure, it also served to support the nozzle guide that ultimately carried the fuel nozzle. Owing to the fact that upstream of the heat shield adjacent the fuel nozzle shows a lower temperature than the heat shield structure, the high thermal stresses tended to reduce the useable life of the heat shield. Because of the heretofore conventional design, the repair and/or replacement was a complex maintenance problem as it required cutting out the heat shield structure from the liner and rewelding a repaired or replacement one.
We have found that we can obviate the problems noted above by separating the higher temperature operating structure from the cooler operating structure permitting uninhibited thermal expansion. Also, in accordance with this invention, removal of the heat shield is simplified and the cost of maintenance thereof is reduced by permitting removal of the heat shield without compromising the supporting combustor liner.